The TOMO-ETNA experiment: an imaging active campaign at Mt. Etna volcano. Context, main objectives, working-plans and involved research projects

Seismic noise recorded by a temporary array installed around Pozzo Pitarrone, NE flank of Mt. Etna, have been analysed with several techniques. Single station HVSR method and SPAC array method have been applied to stationary seismic noise to investigate the local shallow structure. The inversion of dispersion curves produced a shear wave velocity model of the area reliable down to depth of about 130 m. A comparison of such model with the stratigraphic information available for the investigated area shows a good qualitative agreement. Taking advantage of a borehole station installed at 130 m depth, we could estimate also the P-wave velocity by comparing the borehole recordings of local earthquakes with the same event recorded at surface. Further insight on the P-wave velocity in the upper 130 m layer comes from the surface reflected wave observable in some cases at the borehole station. From this analysis we obtained an average P-wave velocity of about 1.2 km/s, compatible with the shear wave velocity found from the analysis of seismic noise.

Section: Introductionmentioning

confidence: 99%

Shallow velocity model in the area of Pozzo Pitarrone, Mt. Etna, from single station, array methods and borehole data

Zuccarello

Paratore

Rocca

et al. 2016

“…The performed calculations are based on the dataset with 184,797 active source rays and 4595 rays from 452 earthquakes [Barberi et al 2016, in this volume]. The active dataset used are those recorded during the refraction experiment of TOMO-ETNA (for more information, see Ibáñez et al [2016a] in this volume). The area analyzed comprises the whole TOMO-ETNA experiment region: from Aeolian Islands to south Mt.…”

Section: Tomo-etna Datasetmentioning

confidence: 99%

“…Previous chapters of this special volume [e.g. Coltelli et al 2016, in this volume;Ibáñez et al 2016aIbáñez et al , 2016b describe the motivation, performance, data acquired and some different approaches of TOMO-ETNA experiment. The most straightforward procedure to study the internal structure of Mt.…”

Section: Introductionmentioning

confidence: 99%

PARTOS - Passive and Active Ray TOmography Software: description and preliminary analysis using TOMO-ETNA experiment’s dataset

Díaz‐Moreno

Koulakov

García-Yeguas

et al. 2016

In this manuscript we present the new friendly seismic tomography software based on joint inversion of active and passive seismic sources called PARTOS (Passive Active Ray TOmography Software). This code has been developed on the base of two well-known widely used tomographic algorithms (LOTOS and ATOM-3D), providing a robust set of algorithms. The dataset used to set and test the program has been provided by TOMO-ETNA experiment. TOMO-ETNA database is a large, high-quality dataset that includes active and passive seismic sources recorded during a period of 4 months in 2014. We performed a series of synthetic tests in order to estimate the resolution and robustness of the solutions. Real data inversion has been carried out using 3 different subsets: i) active data; ii) passive data; and iii) joint dataset. Active database is composed by a total of 16,950 air-gun shots during 1 month and passive database includes 452 local and regional earthquakes recorded during 4 months. This large dataset provides a high ray density within the study region. The combination of active and passive seismic data, together with the high quality of the database, permits to obtain a new tomographic approach of the region under study never done before. An additional user-guide of PARTOS software is provided in order to facilitate the implementation for new users.

“…The TOMO-ETNA field project is a joint research effort of theInstituto Andaluz de Geofísica -University of Granada, Spain, the Istituto Nazionale di Geofisica e Vulcanologia (INGV), Italy, and the GFZ German Research Centre for Geosciences in Potsdam, Germany [see Ibáñez et al 2016aIbáñez et al , 2016b. The project is part of the European Research Project MED-SUV (Mediterranean Supersite Volcanoes).…”

Section: Introductionmentioning

confidence: 99%

“…In the frame of the onshore measurements seismometer stations were deployed around Etna and across Sicily. The recording instruments were provided by the Geophysical Instrument Pool Potsdam (GIPP) established at the GFZ Potsdam in Germany [Ibáñez et al 2016a[Ibáñez et al , 2016b.…”

Section: Introductionmentioning

confidence: 99%

P-wave scattering and the distribution of heterogeneity around Etna volcano

Zieger

Sens‐Schönfelder

Ritter

et al. 2016

Volcanoes and fault zones are areas of increased heterogeneity in the Earth crust that leads to strong scattering of seismic waves. For the understanding of the volcanic structure and the role of attenuation and scattering processes it is important to investigate the distribution of heterogeneity. We used the signals of air-gun shots to investigate the distribution of heterogeneity around Mount Etna. We devise a new methodology that is based on the coda energy ratio which we define as the ratio between the energy of the direct P-wave and the energy in a later coda window. This is based on the basic assumption that scattering caused by heterogeneity removes energy from the direct P-waves. We show that measurements of the energy ratio are stable with respect to changes of the details of the time windows definitions. As an independent proxy of the scattering strength along the ray path we measure the peak delay time of the direct P-wave. The peak delay time is well correlated with the coda energy ratio. We project the observation in the directions of the incident rays at the stations. Most notably is an area with increased wave scattering in the volcano and east of it. The strong heterogeneity found supports earlier observations and confirms the possibility to use P-wave sources for the determination of scattering properties. We interpret the extension of the highly heterogeneous zone towards the east as a potential signature of inelastic deformation processes induced by the eastward sliding of flank of the volcano.